NBS Circulars were compilations of information on various subjects related to the Bureau's scientific, technical, and engineering activities. They included not only the results of Bureau studies, but gave data of general interest from other sources. This series also contained Recommended Specifications, United States Government Specifications, and United States Government Master Specifications formerly issued by the Bureau. These bore a specification number in addition to the Bureau Circular number, but all of these specifications were canceled or superseded by Federal Specifications, which were formulated by the Federal Specifications Board. The series was discontinued in June 1959 and "Circular" material was directed to the NBS/NIST Journal of Research and the Monograph series.